(1) Field of the Invention
This invention relates to electrosurgery and more particularly preventing grounding pad burns on a patient.
(2) Description of the Prior Art
Those skilled in the art of electrosurgery are familiar with the problem of severe burns to the patient at the location of attached grounding pads. A radio frequency (RF) source utilizes a high density current for localized coagulating or cutting. Grounding pads are connected to the patient who must be at a zero or ground potential electrically.
Several devices have previously attempted to solve the problem associated with an inactive electrode ground plate. All of these devices utilize the common design of measuring a change in current resulting from the loss of a solid ground connection to the patient.
Before this application was filed, applicant caused a search to be made in the U.S. Patent and Trademark Office at which time all of the following patents were found:
HOOD, U.S. Pat. No. 2,660,717
CROWLEY, U.S. Pat. No. 3,628,093
ANDERSON, U.S. Pat. No. 3,683,923
NEWTON, U.S. Pat. No. 4,094,320
GONSER, U.S. Pat. No. 4,121,590
BLACKETT, U.S. Pat. No. 4,122,854
The NEWTON patent, which was assigned to Valleylab, Inc., utilizes a complex electronic circuit to monitor currents associated with a ground plate. The BLACKETT patent, which was assigned to Matburn (Holdings) Limited, uses a voltage sensitive circuit while the patient is grounded by a ground plate. Similarly, ANDERSON, which was assigned to Valleylab, Inc., utilizes a current sensing circuit for use with a grounding plate. CROWLEY discloses a temperature responsive protection system for electric appliances (blanket) and is not related to the medical profession. GONSER, which was assigned to Dentaply Research and Development Corporation, utilizes a voltage and current limiting circuit where a ground plate is used. HOOD does not appear to be pertinent to applicant.
The prior art has consistently tried to solve the problem by measuring currents and voltages when a faulty patient ground existed.